java servlet项目和eclipse中的android库项目 - NoClassDefFoundError [英] java servlet project and android library project in eclipse - NoClassDefFoundError

问题描述

我的工作区有一些项目：

  AndroidMonitoring＃一个android应用程序
 MonitoringModel＃一个android库项目
 DataServlet＃servlet project 
  

AndroidMonitoring（依赖于MonitoringModel，

）

编译并运行正常，但我需要在DataServlet项目中也可以使用MonitoringModel类。我在DataServlet项目的Java Build路径中添加了Model作为依赖，但是我得到：

  java.lang.NoClassDefFoundError： gr / uoa / di / monitoring / model /电池
 gr.uoa.di.monitoring.server.servlets.DataCollectionServlet.doGet（DataCollectionServlet.java:20）
 javax.servlet.http.HttpServlet.service （HttpServlet.java:621）
 javax.servlet.http.HttpServlet.service（HttpServlet.java:722）
  

我需要模型是一个Android库项目，因为它包含android类 - 而且还包含解析servlet中的文件的方法 - 是可能吗？如何设置？

编辑：MonitoringModel是 here

解决方案

已解决

1. 从DataServlet的java构建路径中删除依赖关系


2. 转到 MonitoringModel 项目和删除库属性，将其作为Android应用程序运行，将其重新映像到库中（从此处）清理MonitoringModel项目


3. 从bin /中获取monitormodel.jar，并将其放入 DataServlet / WEB-INF / lib


4. 刷新并在服务器上运行


5. 完成！

将尝试改进这个黑客（链接到外部jar似乎没有工作btw） - 任何更好的想法将被接受作为答案 - 但现在关闭这个。

编辑：显然步骤3.可以通过从 DataServlet / WEB-INF / lib / monitoringmodel.jar 创建一个硬连接替代为monitormodel.jar - 仍然将其作为一些操作序列进行测试打破链接。符号链接似乎不起作用 - 报告为错误

EDIT2 ：以下步骤似乎也可以工作，但是我留下手动过程，因为它绝对有效

1. 从DataServlet的java构建路径中删除依赖关系



2. 将monitormodel.jar从bin /连接到code> DataServlet / WEB-INF / lib中。我使用shell链接扩展名，但是这样：

     mklink / H c：\path\to\WebContent\WEB- INF \lib\monitoringmodel.jar c：\path\to\bin\monitoringmodel.jar 
     

   也应该工作




3. 现在每当您更改监控模型时，jar都会更新。您只需要刷新 servlet项目（默认情况下将自动重新部署在服务器上）

$ b $澄清：当然，servlet项目不是要使用 android。* 类 - 这不是我的问题 - 我的问题是让模型代码在一个地方，这个地方必须是一个Android库

I have some projects in my workspace :

AndroidMonitoring # an android application
MonitoringModel # an android library project
DataServlet # servlet project

AndroidMonitoring (which depends on MonitoringModel,

)

compiles and runs just fine but I need the MonitoringModel classes to be available also in the DataServlet project. I added the Model as a dependency in the Java Build path of the DataServlet project but I get :

java.lang.NoClassDefFoundError: gr/uoa/di/monitoring/model/Battery
    gr.uoa.di.monitoring.server.servlets.DataCollectionServlet.doGet(DataCollectionServlet.java:20)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

I need the Model to be an Android library project as it contains android classes - but also contains the methods to parse the files in the servlet - is it possible ? How should I set this up ?

EDIT : MonitoringModel is here

解决方案

Solved !

1. remove the dependency from DataServlet's java build path
2. go to the MonitoringModel project and remove the library attribute, run it as an Android app remake it into a library (from here) Clean the MonitoringModel project
3. grab the monitoringmodel.jar from bin/ and drop it into the DataServlet/WEB-INF/lib
4. refresh and run on server
5. done !

Will try and improve on this hack (linking to an external jar did not seem to work btw) - any better ideas will be accepted as an answer - however closing this for now.

EDIT : apparently step 3. can be substituted by creating a hard link from DataServlet/WEB-INF/lib/monitoringmodel.jar to monitoringmodel.jar - still testing this as some action sequences break the link methinks. Symbolic links do not seem to work though - reported this as a bug

EDIT2 : the steps below seem to work too - but I leave the manual procedure as it definitely works

1. remove the dependency from DataServlet's java build path

2. Hard link the monitoringmodel.jar from bin/ and to the DataServlet/WEB-INF/lib. I used shell link extension but this :

   mklink /H c:\path\to\WebContent\WEB-INF\lib\monitoringmodel.jar c:\path\to\bin\monitoringmodel.jar
   

   should also work

3. Now everytime you make a change in monitoring model the jar is updated. You only have to refresh the servlet project (will be redeployed on server on its own by default)

_{Clarification : of course the servlet project is not meant to use android.* classes - this was not my issue - my issue was to have the model code in one place and this place had to be an android library}

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